In general, a voltage detection device performs detection, for example, with the use of an A/D conversion device for complicated signal processing or an interface with a microprocessor. The use of the A/D conversion device in a multi-mode where, for example, a ΔΣ system and a pipeline system are combined together has been proposed (for example, refer to Patent Document 1). In addition, the present applicant has proposed a technique used in a hybrid mode where the ΔΣ system and a cyclic system are combined together (for example, refer to Patent Document 2).
(Patent Document 1)
Publication of Unexamined Japanese Patent Application No. 2011-66626
(Patent Document 2)
Publication of Unexamined Japanese Patent Application No. 2015-133626
It is conceivable to apply such an A/D conversion device to a detection process for a charging voltage across battery cells in an assembled battery and to a voltage detection process during a failure diagnosis. It is conceivable to enhance a voltage detection accuracy in order to improve a monitoring of a charging state of the battery cell or to improve a calculation performance of the charging amount. In this case, an A/D conversion processing is performed with a high voltage detection accuracy even when the A/D conversion device is used for the voltage detection process during the failure diagnosis.
From the viewpoint of safety of the system, when a failure in more circuit blocks is diagnosed, it takes much processing time related to the failure diagnosis, and a diagnosis schedule becomes overcrowded. As a result, the entire diagnosis process cannot be completed within a predetermined period. In addition, the safety of the system may be likely to be impaired. For that reason, the safety of the system is required to be ensured while the voltage detection accuracy of the battery cell is improved. In addition to such a case, there is a need to adapt the detection accuracy and the processing time to various states, and the detection accuracy and the processing time are required to be flexibly changeable according to an object to be detected.